APCI (atmospheric pressure chemical ionization) and ESI (electrospray ionization) are the two most frequently utilized mass detection tools for automated flash chromatography.  In a previous post, I discussed differences between the two detectors and the compound types best suited for each source.

Because these two sources ionize differently, there are cases when additives are needed in the make-up solvent and cases when they should not.  In this post, I will show the impact that adding a buffer or acid has on APCI detection.

In previous posts I have discussed some options and techniques to improve detection of poorly absorbing or UV-transparent compounds – by wavelength focusing and by evaporative light-scattering (ELS).

In this post I will talk about a third alternative technique – using an in-line mass detector.

An interesting question, at least to me. Depending on the detector brand, some mass spectrometer manufacturers recommend acetonitrile while others recommend methanol. Is there a real difference between these solvents?

In this post I look at how acetonitrile and methanol compare when used with an APCI source.